1. Ahh!
Can’t We
Just Watch
The Movie?
HEREDITY

2. But what film should we use?
Well, what if we use a movie to help understand heredity and genetics?
But what film should we use?

4. Harry Potter and the Recessive Allele
How Are Wizards Made?

5. How Are Wizards Made?
Being a wizard or a muggle is all decided by genetics
All humans including
wizards receive one
allele from each parent

6. Muggleness
Being a muggle is a dominant trait, represented by M. To be a muggle, you must have inherited an M from one of your parents. The allele options could be MM or Mm. If you have the M, you will have the dominant trait.

7. Wizards Wizards have the alleles (m m)
The allele for wizarding ability is: (m)
Wizards have
the alleles
(m m)

8. Muggles The allele for Muggleness is (M) Muggles have the
alleles (M m) or (M M)
(M) is dominant to (m)
Wizards only have (mm)

9. The Malfoys Narcissa Malfoy (m m) Lucius Malfoy (m m) Draco Malfoy W
The Malfoys are a ‘pure blood’ family
All their ancestors are wizards so they must have the alleles (m m)

10. They passed these alleles on to Harry
The Potters
James Potter (m m)
Lily Potter (m m )
Harry Potter (m m)
Both Harry’s parents had magical ability so they must both have been (m m)
They passed these alleles on to Harry

11. The Weasleys are pure blood wizards so they
all have the alleles ( m m )

12. Hermione is a Powerful Witch. Therefore, she must be (m m).
However, both her parents are muggles so they must be (M m) so they can give her a (m) allele each.
(Mm)
(Mm)
(m m)

13. (m m) (M m) (m m) Tom Riddle is a ‘half blood’.
His mother was a witch (m m) and his father was a muggle
His father must have had the alleles (M m) so he could give him the other m allele
(m m)
(M m)
(m m)

14. This means he has a mutation so his wizarding powers don’t
Filch is a ‘Squib’
Both his parents are (m m) so he should be too because he can’t get an (M) allele from either parent but he can’t do any magic
This means he has a mutation
so his wizarding powers don’t
work or the man he thinks is his
father is not truly his father.
His natural father must
be a muggle!

16. What Wizarding Alleles Would Ron and Hermione’s Children Have?
Ron (m m)
Hermione (m m)
Children
( m m )

17. Their children could only get the (m) allele from both parents so they would all be wizards
Ron m
Hermione
m m
m m
m m
m m

18. Dudley Ginny (M m) or (MM) (m m) (M m) or (m m)
What Wizarding Alleles Would Ginny and Dudley’s
Children Have If Dudley is (M m)?
Dudley
(M m) or (MM)
Ginny
(m m)
(M m) or (m m)

19. Half of their children would be likely to get the w allele from both parents so they would be wizards
The other half would be likely to get an (M) allele from Dudley and would be muggles
Dudley m M
Ginny mm Mm mm Mm

20. But what if Dudley was pure muggle (M M)?
Their children would get the w allele from Ginny and the (M) allele from Dudley so they would all be muggles
Dudley M
Ginny m Mm Mm Mm Mm

21. What wizarding alleles would you expect Hermione’s brothers and sisters to have?

22. The Granger’s children have a 1 in 4 chance of getting (m) alleles from both parents and having magical ability
They also have a 1 in 4 chance of getting (M) alleles from both parents and being a muggle
They could also
get only one
(m) from their
mother or father
and still be a
muggle
Mr Granger m M
Mrs Granger mm Mm MM

23. Congratulations!
You are now an expert
on Wizard Genealogy.

24. The
End